It worked fine, the piezo driver sat on, aimed into a piece of 3/4" EMT electrical tubing, driven into the ground 6+ feet. By setting the frequencies a bit higher and making it simply oscilate instead of "warble" ... around 28K Htz., then it didn't bother the dog at all. The theory is that it messes with the gophers' sex life, somehow, so they go away. The ants all went away as well.

Only there as an example !
Puts 24V square across the piezo without transformer.

I had one with three Motorola piezos and LM3900 warble driving a capacitor firing transistor npnp arrangement and step-up transformer (pcb about 1 x1 x2 inches) each but can't find the circuit I developed.
The beats were unbearable.

Was being designed as an airport bird scarer, one box could scare birds up to 1/2 mile.

Motorolas very directional at hf, thus if aimed into a neighbours garden will work over a very narrow range.

" ... Was being designed as an airport bird scarer, one box could scare birds up to 1/2 mile. ... Motorolas very directional at hf, thus if aimed into a neighbours garden will work over a very narrow range. ..."

Yes they are as are most higher freq. drivers. (If memory serves, something like 15 degrees off axis was max radiated pattern, narrower at higher freq.) = good for local doggie go go getter as it won't interfer too much with the whole neighborhood's other doggies.

Birds!! ... at airports !! I would have thought something more like a recording of the bigger hawks, played back would do it for the little birdies, pigeons, etc. ... and I would imaging you would have trouble with non-omnidirectionallity of the drivers as above = same as for doggies. (Is there a word like non-omnidirectionallity ? ... maybe it should be just "directionality" ...)

[Off topic a little: I have always wanted to record the Hooded Monk Finch ond some other Finch songs ... mostly way above human hearing range, 12K Htz. and up to above 25K Htz. ... digitally, then using some kind of frequency division technic to drop their tunes [play list?] down to a human listenable bandwidth without out losing content, etc. ... anyone every hear about doing anything like this?]